Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

src/timer/windows/SDL_systimer.c

@@ -0,0 +1,198 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_TIMER_WINDOWS
+
+#include "../../core/windows/SDL_windows.h"
+#include <mmsystem.h>
+
+#include "SDL_timer.h"
+#include "SDL_hints.h"
+
+
+/* The first (low-resolution) ticks value of the application */
+static DWORD start = 0;
+static BOOL ticks_started = FALSE; 
+
+/* Store if a high-resolution performance counter exists on the system */
+static BOOL hires_timer_available;
+/* The first high-resolution ticks value of the application */
+static LARGE_INTEGER hires_start_ticks;
+/* The number of ticks per second of the high-resolution performance counter */
+static LARGE_INTEGER hires_ticks_per_second;
+
+static void
+SDL_SetSystemTimerResolution(const UINT uPeriod)
+{
+#ifndef __WINRT__
+    static UINT timer_period = 0;
+
+    if (uPeriod != timer_period) {
+        if (timer_period) {
+            timeEndPeriod(timer_period);
+        }
+
+        timer_period = uPeriod;
+
+        if (timer_period) {
+            timeBeginPeriod(timer_period);
+        }
+    }
+#endif
+}
+
+static void
+SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
+{
+    UINT uPeriod;
+
+    /* Unless the hint says otherwise, let's have good sleep precision */
+    if (hint && *hint) {
+        uPeriod = SDL_atoi(hint);
+    } else {
+        uPeriod = 1;
+    }
+    if (uPeriod || oldValue != hint) {
+        SDL_SetSystemTimerResolution(uPeriod);
+    }
+}
+
+void
+SDL_TicksInit(void)
+{
+    if (ticks_started) {
+        return;
+    }
+    ticks_started = SDL_TRUE;
+
+    /* if we didn't set a precision, set it high. This affects lots of things
+       on Windows besides the SDL timers, like audio callbacks, etc. */
+    SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
+                        SDL_TimerResolutionChanged, NULL);
+
+    /* Set first ticks value */
+    /* QueryPerformanceCounter has had problems in the past, but lots of games
+       use it, so we'll rely on it here.
+     */
+    if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
+        hires_timer_available = TRUE;
+        QueryPerformanceCounter(&hires_start_ticks);
+    } else {
+        hires_timer_available = FALSE;
+#ifndef __WINRT__
+        start = timeGetTime();
+#endif /* __WINRT__ */
+    }
+}
+
+void
+SDL_TicksQuit(void)
+{
+    if (!hires_timer_available) {
+        SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,
+                            SDL_TimerResolutionChanged, NULL);
+    }
+
+    SDL_SetSystemTimerResolution(0);  /* always release our timer resolution request. */
+
+    start = 0;
+    ticks_started = SDL_FALSE;
+}
+
+Uint32
+SDL_GetTicks(void)
+{
+    DWORD now = 0;
+    LARGE_INTEGER hires_now;
+
+    if (!ticks_started) {
+        SDL_TicksInit();
+    }
+
+    if (hires_timer_available) {
+        QueryPerformanceCounter(&hires_now);
+
+        hires_now.QuadPart -= hires_start_ticks.QuadPart;
+        hires_now.QuadPart *= 1000;
+        hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
+
+        return (DWORD) hires_now.QuadPart;
+    } else {
+#ifndef __WINRT__
+        now = timeGetTime();
+#endif /* __WINRT__ */
+    }
+
+    return (now - start);
+}
+
+Uint64
+SDL_GetPerformanceCounter(void)
+{
+    LARGE_INTEGER counter;
+
+    if (!QueryPerformanceCounter(&counter)) {
+        return SDL_GetTicks();
+    }
+    return counter.QuadPart;
+}
+
+Uint64
+SDL_GetPerformanceFrequency(void)
+{
+    LARGE_INTEGER frequency;
+
+    if (!QueryPerformanceFrequency(&frequency)) {
+        return 1000;
+    }
+    return frequency.QuadPart;
+}
+
+void
+SDL_Delay(Uint32 ms)
+{
+    /* Sleep() is not publicly available to apps in early versions of WinRT.
+     *
+     * Visual C++ 2013 Update 4 re-introduced Sleep() for Windows 8.1 and
+     * Windows Phone 8.1.
+     *
+     * Use the compiler version to determine availability.
+     *
+     * NOTE #1: _MSC_FULL_VER == 180030723 for Visual C++ 2013 Update 3.
+     * NOTE #2: Visual C++ 2013, when compiling for Windows 8.0 and
+     *    Windows Phone 8.0, uses the Visual C++ 2012 compiler to build
+     *    apps and libraries.
+     */
+#if defined(__WINRT__) && defined(_MSC_FULL_VER) && (_MSC_FULL_VER <= 180030723)
+    static HANDLE mutex = 0;
+    if (!mutex) {
+        mutex = CreateEventEx(0, 0, 0, EVENT_ALL_ACCESS);
+    }
+    WaitForSingleObjectEx(mutex, ms, FALSE);
+#else
+    Sleep(ms);
+#endif
+}
+
+#endif /* SDL_TIMER_WINDOWS */
+
+/* vi: set ts=4 sw=4 expandtab: */